Steel 55X
Steel 55Х
Steel 55X: Handbook of steels and alloys. Below is systematized information on the purpose, chemical composition, types of supply, substitutes, critical point temperature, physical, mechanical, technological and foundry properties for the grade — Steel 55X.
General information on steel 55X
| Type of delivery |
| Rolls OST 24.013.20−85, OST 24.013.21−85, OST 24.013.04−83. Forging GOST 8479−70. |
| Application |
| Axes of composite support rolls for cold rolling of metals. Working rolls of blooming, slabbing, billet, rail, heavy-grade, medium and low-grade mills and working rolls of sheet mills for hot metal rolling. Gear shafts, gears and other loaded parts subjected to abrasion, but working without significant shock loads. |
Chemical composition of steel 55X
| Chemical element |
% |
| Silicon (Si) |
0.17−0.37 |
| Manganese (Mn) |
0.35−0.65 |
| Nickel (Ni), not more |
0.50 |
| Sulfur (S), not more than |
0.040 |
| Carbon (C) |
0.50−0.60 |
| Phosphorus (P), not more than |
0.040 |
| Chromium (Cr) |
1.0−1.3 |
Mechanical properties of steel 55X
Mechanical properties at elevated temperatures
| t test,°C |
σB, MPa |
δ5, % |
ψ, % |
| Superheating temperature 1220 °C, holding time 15 min. Movement speed of the test machine grips 150 mm/min |
| 700 |
190 |
52 |
65 |
| 800 |
115 |
56 |
80 |
| 900 |
78 |
83 |
99 |
| 1000 |
54 |
89 |
100 |
| 1100 |
40 |
99 |
100 |
| 1220 |
27 |
|
100 |
Mechanical properties of forgings
| Heat treatment, delivery condition |
Section, mm |
σ0, 2, MPa |
σB, MPa |
δ5, % |
ψ, % |
KCU, J/m2 |
HB |
| Forgings. Hardening. Tempering. KP 490 |
<100 |
490 |
655 |
16 |
45 |
59 |
212−248 |
Mechanical properties of forgings depending on the cross-section
| Section, mm |
σ0, 2, MPa |
σB, MPa |
δ5, % |
ψ, % |
KCU, J/m2 |
HB |
| Tempering at 820−840°C, oil. Tempering 560−630°C, furnace or air. |
| 100 |
640 |
840 |
12 |
40 |
|
255−322 |
| 101−300 |
540 |
780 |
10 |
35 |
|
240−302 |
| 301−500 |
490 |
730 |
8 |
30 |
|
240−300 |
| Normalization 840−860°C, air. Tempering 580−630°C, air or furnace. |
| 301−500 |
340 |
640 |
8 |
30 |
|
210−240 |
| Forging temperature 1210 °C, holding time 10 h. Isothermal annealing. Normalization. High tempering. |
| 480 |
380 |
780 |
13 |
22 |
21 |
|
| 670 |
|
760 |
|
|
|
|
| 960 |
340 |
750 |
9 |
15 |
18 |
|
Technological properties of steel 55Х
| Forging temperature |
| The beginning 1220, the end 800. Sections up to 200 mm are cooled in the air, 200−350 mm — in the pit. |
| Weldability |
| Difficult-to-weld. Welding methods: RDS, heating and subsequent heat treatment is necessary. TIG, following heat treatment is necessary. |
| Machinability by cutting |
| In the normalized condition at HB 217−229 σB = 720 MPa Kυ dv.spl. = 0.8, Ku b.st. = 0.6. |
| The tempering capacity |
| inclined |
| Flocke sensitivity |
| sensitive |
Steel hardness 55X
| Delivery condition, heat treatment regime |
NV |
| Axes of composite support rolls. Volumetric heat treatment. |
220−280 |
| Rolls barrels of cogging and section mills for hot rolling. Section up to 1500 mm. Normalization. Tempering. |
223−277 |
| Rolls barrels of cogging and bar mills for hot rolling. Cross-section up to 1500 mm. Hardening. Tempering. |
255−293 |
| Barrels of work rolls of sheet mills for hot rolling. Section up to 1000 mm. Normalization. Tempering. |
223−277 |
| Drums of working rolls of sheet mills for hot rolling. Section up to 1000 mm. Hardening. Tempering. |
255−293 |
